UPDATE: Journal Publishes CDC Paper Failing to Find Viral Link With Chronic Fatigue Syndrome

It is the latest in a slew of conflicting findings. Last year, a Nevada team reported in Science an association between XMRV and CFS, a mysterious disease that has no known cause. Since then, three European studies have found no XMRV connection, and now CDC has not in U.S. patients, either. But another U.S. government team has: Researchers at the U.S. National Institutes of Health (NIH) and Food and Drug Administration (FDA) have a paper accepted at the Proceedings of the National Academy of Sciences (PNAS) that confirms the connection. Government officials and PNAS and, until today, Retrovirology, have held off on publishing the two new papers because of the clashing conclusions between U.S. agencies.

CDC virologist William Switzer, lead author of the Retrovirology paper, explains that after taking "a scientific pause" and conferring with their NIH and FDA colleagues, the CDC team concluded that nothing in their paper needed to be revised and that "we would go forward" with publication. The paper discusses possible reasons for the discordant results, such as differences in how patients were recruited. (The authors of the Science paper found them through doctors, whereas CDC recruited a chronic fatigue group through telephone surveys in Georgia and Wichita, Kansas.)

More answers may come from a study organized by the NIH's National Heart, Lung and Blood Institute to have several labs test the same set of blinded clinical samples for XMRV. Four U.S. government labs and two outside labs are participating, including the researchers at the Whittemore Peterson Institute in Reno, Nevada, who wrote last year's Science paper. The testing should be completed by the end of the year, Switzer says.

PNAS declined to comment on a query asking when the NIH-FDA paper will be published.

UPDATE 2 July: The authors of the PNAS paper have decided it needs more work. Corresponding author Harvey Alter of the NIH Clinical Center, who is in Berlin this week, issued this statement on 30 June: "Our paper has not yet been accepted for publication. My colleagues and I are conducting additional experiments to ensure that the data are accurate and complete. Our goal is not speed, but scientific accuracy." NIH spokesperson John Burklow explained to Insider that the paper had been accepted, but Alter and his co-authors decided to "pull it back" and revise it in response to questions raised by reviewers.